A vast winter storm is set to descend across much of the US starting on Friday, sweeping snow, ice and brutal cold across nearly 2,000 miles from the south-west to the east coast and affecting more than 200 million people.
The system is expected to disrupt travel, bring down trees and power lines, and create the risk of prolonged power outages, followed by dangerously cold air.
By this weekend the storm is predicted to affect a long list of major cities, from Dallas and Oklahoma City to Memphis, Nashville, St Louis and Indianapolis, before moving farther east into Louisville, Charlotte, Norfolk, Washington, Baltimore, Philadelphia and New York.
The storm is also likely to reach into the Great Lakes and New England, affecting Pittsburgh, Cleveland, Buffalo and Boston. Some areas along this path could see more than a foot of snow, while others may contend with severe ice buildup.
Forecasters expect the storm to peak on Sunday, when roughly 55% of the population of the contiguous US will be experiencing snow, sleet or freezing rain simultaneously.
What makes this system particularly dangerous is not just the precipitation but the extreme cold tied to it. As the polar vortex plunges southward, temperatures in parts of the midwest, Great Lakes and New England are forecast to drop below minus 30F.
When the frigid air collides with moisture flowing in from both the Pacific Ocean and the Gulf of Mexico, it will fuel what is shaping up to be the most powerful winter storm of the season so far, followed by lingering cold.
“We’re about to witness a truly legendary winter storm setup in the Southern US later this week,” the defense department meteorologist, Eric Webb, wrote on X, adding that the storm will contain “a ridiculous amount of snow/ice”.
Those conditions will first take shape in the Rockies and Plains on Friday before expanding eastward through the weekend. The system is not expected to fully release its grip on the east coast until early next week. Cities such as Denver, Albuquerque, Wichita and Oklahoma City are expected to be among the first affected. Accumulating snow will also reach parts of Wyoming, Colorado and New Mexico.
On Saturday, more than 100 million people could be affected at once. A broad zone from northern Texas through Kentucky may see 6-12in of snow on average, while farther south a dangerous ice storm could stretch from Texas into the Carolinas, making travel along major highways hazardous.
With power outages possible, residents in the most affected areas have been advised to prepare, including by fueling generators, picking up medications and securing water and non-perishable food. Gusty winds of 20 to 30mph could lead to blowing snow and snapped, ice-coated branches.
On Sunday the heart of the storm will shift toward the east coast, with the heaviest snow thought to be centered over the mid-Atlantic, putting Washington and Baltimore in line for major accumulations before finally moving offshore late on Sunday, though snow may linger across parts of the north-east.